4 Lug bolt pattern: 4x4.5(4x114.3)
5 Lug bolt pattern: 5x4.5(5x114.3)
Studs are m12x1.25
Centerbore is 66.1mm
Stock wheel offset:
Pictures of all stock wheels are here!
There were at least 8 different wheels on early 300ZXs in two different bolt patterns. 84-85 had the decent looking 4 lug 5 star wheels(15x6.5), 84 turbos had the same 5 star wheels but with the 5 lug pattern in 15x6.5 on non anniversiary models, anniversary models had the 16x7 wheels with lots of short spokes arouns the edge. 86 non-turbos had 5 lug wheels with a center cap that surrounded the lugnuts but didn't cover them. 86 turbo wheels are the same as 84 anniversary model wheels. With the more rounded front end in 87 came decent looking 5 lug wheels with a big center cap that covered the lugnuts completely. These had lots of small spokes around the outside edge. All non-turbos were plain aluminum, 87 turbos had "charcoal tint"(They were a slightly transparent black, very cool), 88 and 89 turbos were uncolored, except for the 88se, which had white wheels to match its unique pearl white paint.
If you have a 4 lug car and want to put 5 lug wheels on it, you can, but it takes some work. The front is easy to do, get the 5 lug hubs, 5 lug rotors, and calipers from an 84-86 5 lug car and bolt them on. As far as I know, they are completely interchangable. The rears however are a different story. It's nearly impossible to get the rear stub nut off to get to the rear bearings, and if you do get it off, it won't do you any good! The 5 lug cars had different rear wheels bearings and races, and spindles, etc. You will need the entire rear control arm assembly to get a 5 lug hub in the rear. The control arm thankfully bolts right in. Make sure you get the one that takes your half-shafts, they are different on turbos and non-turbos. All companion flanges fit onto all stub axles, so they are easy to swap around.
Yes, you can put wheels from a 90-96 300ZX on your car. They fit straight on the rear, no modifications necessary. To fit the rear twin turbo wheels to the front of your car(84-86) you'll need 5/8 inch spacers, longer studs, and different lugnuts. To fit front twin turbo or non-turbo wheels to the front of your car(84-86) you'll need a one inch spacer, longer studs, and different lugnuts. To do the same on 87-89 cars you can use a slightly thinner spacer because of the bigger angle between the strut housing and the axle stub. You would probably want to put the same spacers on the rear wheels anyhow so it doesn't look funny and mess up your handling. This of course requires the longer studs and different lugnuts. The long studs are available from Nissan Motorsports and are only $8. I mean they're $8 a piece, as in a bolt that costs $8. According to my intuitive math skills that is $160 just for wheel studs. Still wanna do it? Or you can get 'murican threaded studs from auto zone that fit and use 'murican lugnuts. Just don't forget when you're taking them off! "Reaching lugnuts" have also been reported to work, but I no nothing specific about them.
99-00 mustang cobra wheels (not cobra r) fit fine as well, but only on 87-89 cars. And at $150(tire rack) new in 17x8 +30, they are a very good deal. 245-40-17 will keep your gearing and speedometer correct as well. Here is an 87-89 with 98 cobra wheels. 98 cobra wheels are 17x8 +32 and apparently fit fine on 87-89 with no spacers. 84-86 will need spacers to fit any of these cobra wheels.
Offset is the distance from the mounting plane to the center line of
a wheel. Positive offset means the mounting plane is on the outer side of
the centerline, negative offset means the opposite. The picture
to the left shows positive offset. Backspacing is the distance from the
innermost part of a wheel to the mounting plane.
backspacing=offset + wheelwidth / 2
Note that the sign of the offset matters!